I am pretty sure this number and (03) 5520 3390 belong to the same people. I got a call at 8am WAST did not answer, no voice message left.
2 hours later got another call, from this number and it was a automatic message advising my "Amazon Prime Account" will be charged extra for whatever random reason did not paid attention at all because I do not have Amazon Prime. They wanted me to press 1 to speak with a customer service person... just hanged up.